Coil formation in an electric machine with concentrated windings

Abstract

Provided is an electric generator including a stator including:a stator yokea plurality of teeth,a plurality of slots extending radially from the stator yoke to respective radial slot ends, the plurality of slots being circumferentially interposed between the teeth of the stator, each slot including a bottom portion adjacent to the stator yoke and a top portion adjacent to the respective radial slot end. The stator further includes a plurality of coils housed in the plurality of slots, each slot housing at least one coil in the bottom portion and at least another coil in the top portion, each coil housed in the bottom portion of a first slot of the plurality of slots being connected to another respective coil housed in the top portion of a second slot of the plurality of slots.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to PCT Application No. PCT / EP2019 / 058345, having a filing date of Apr. 3, 2019, which is based off of EP Application No. 18167999.4, having a filing date of Apr. 18, 2018, the entire contents both of which are hereby incorporated by reference.FIELD OF TECHNOLOGY[0002]The following relates to an electric machine with concentrated windings having a coil geometry permitting an increase of the fill factor, i.e. the ratio between the winding which is made of a good conducting material and the volume needed to house the winding.[0003]The following may be particularly, but not exclusively, applied to the electric generator of a wind turbine.BACKGROUND[0004]An electrical machine, such as an electric generator installed in a wind turbine, typically comprises a rotor which rotates relative to a stator.[0005]The stator normally comprises a frame body longitudinally extending along a longitudinal axis and including a ...

AI Technical Summary

Benefits of technology

The technical effects of this patent text are as follows: 1. The patent provides an electric generator with a stator geometry that reduces the coil overhang length, improving the generator's performance without compromising its ability to produce power. 2. The stator geometry allows for easy insertion of coils into the slot without damaging their insulation, and increases the fill-factor of conducting material in the slot compared to conventional options. 3. The stator coils are organized into two electrical phases, and all the coils in the bottom portion belong to the first phase and all the coils in the top portion belong to the second phase, avoiding the need for insulation between coils of the same phase.

Problems solved by technology

In such design the double layer winding layout makes it difficult to insert coils with narrow coil width for side by side coil formation.

Also, there is a possibility to damage the coil insulation during coil insertion process.

This design eases the coil insertion with shorter coil overhang length but it reduces performance of the machine as active material of tooth is replaced by non-active insulation material 16a in the middle of each slot, between the coils.

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